1. Field of the Invention
The present invention relates to a nanosilicon light-emitting element that can emit light in the three primary colors (red, green, blue), and particularly that can emit blue light clearly and in a stable manner under a low voltage; and to a manufacturing method thereof.
2. Description of the Related Art
The present invention also relates to the establishment of a manufacturing process for the nanosilicon light-emitting element and to the development of a nanosilicon-type electroluminescence element. These can be utilized in the sections of light-emitting elements that are incorporated in electroluminescence displays, light-emitting diodes, and other such display devices, or optoelectronic elements and other such optical communication devices, and are therefore expected, as a result of the development of the present invention, to have wide applications in the near future in the versatile field of optoelectronics, including color displays, portable display panels, and the like.
Mainstream light-emitting elements currently use expensive materials that put a great strain on the global environment, which is causing problems that must quickly be solved. Therefore, it is an urgent matter that inexpensive materials that are easy on the natural environment and that make energy conservation possible be used in the development of future light-emitting elements. Nanosilicon is expected to serve as a material that satisfies all of these conditions. Nanosilicon is a material that has been researched since 1980, and exhibits various qualities that are not found in silicon crystals. The luminescence of nanosilicon is the most typical example of such qualities. This luminescence is a result of the band gap energy expanding to the visible region due to the reduction of the size of silicon crystals to a region in which quantum confinement occurs (4.3 nm or less). According to Japanese Patent Application Laid-open No. H7-237995, it has been difficult to reduce the size of silicon crystals in a stable manner, to emit light under a low voltage, and particularly to emit blue light clearly and in a stable manner.
The color of light emitted by a light-emitting element is directly affected by the size of the nanosilicon, and emitted light ranging from red light to blue light is presently being obtained from porous silicon, which is one example of nanosilicon-type material. With porous silicon, however, test specimens are severely degraded, so emission life or intensity cannot be increased, and the material has been regarded as difficult to apply to light-emitting elements. Therefore, the development of nanosilicon capable of long-lasting and luminescent multicolored light emission is considered urgent for practical application in light-emitting elements.